Tape measure with lock button

ABSTRACT

A tape measure includes a housing having first and second half and a bottom access door which is openable to provide an access port to the interior of the housing. A spool is rotatably mounted upon an axle which has an integrally formed ratchet plate. The ratchet plate engages ratchet teeth that are integrally formed within the interior surface of the housing to provide for rotation of the axle to load a spring within the spool to a desired tension. The ratchet teeth normally prevent rotation of the axle to unload the spring tension. An overriding mechanism allows the axle to axially move to disengage the ratchet plate from the ratchet teeth to provide for rotation of the axle to unload the spring mechanism. A lock button has a thumb operating section at the top portion of the housing and has a pressure regulating section which regulates the pressure that the bottom end of the lock button exerts against the tape.

This application is a continuation-in-part of application Ser. No. 622,683, filed June 20, 1984, now abandoned.

TECHNICAL FIELD

This invention generally relates to tape measures and more particularly, to a tape measure with a releasable lock switch.

BACKGROUND DISCLOSURE INFORMATION

One very popular type of tape measure has a spool which is spring loaded within a housing. A coilable tape is wrapped about the spool and extends through a slot to the outside of the housing. The end of the tape has a hook which allows it to be hooked onto the object to be measured and in addition, retains the outer end of the tape at the slot for easy grasping of the tape.

A major problem with these tapes are that when the tab breaks, the spool is then free to rotate in a direction that unwinds the spring and retracts the end into the housing. Once the end is retracted, the tape cannot be retrieved without taking the housing apart. If the housing is taken apart, the spool is displaced from its rotatably mounted position and the tape under its own spring force often uncontrollably uncoils from the spool. Because of the great difficulties in replacing a tape in the present housing and spool assemblies, one commonly throws out the tape measure when the tape breaks and buys a new one, even though the spool and housing are in perfect condition.

Attempts have been made to market a cartridge which includes a spring, spool and tape to replace the old cartridge within the old housing. See U.S. Pat. Nos. 3,716,201 issued to West on Feb. 13, 1973, and U.S. Pat. No. 3,689,004 issued to Brown and Stoutenberg on Sept. 5, 1972. However, the housing must still be taken apart to replace these cartridges. Secondly, the cost of the cartridge is comparable with buying a new tape measure. Consequently, consumers would rather spend a little extra money and obtain a new, shiny, undented housing without having any aggravation in controlling an uncoiling tape.

Furthermore, attempts have been made to adjust the spring after the cartridge has been inserted within the housing.

Many tapes have releasable lock switches that are usually slidably mounted in the front wall of the housing. However, the position at the front provides a relatively uncomfortable position and is inaccessible when the tape measure is held in a comfortable manner.

What is needed is a tape measure assembly that provides access to the spool without the need to dismount the spool from within the housing in order to replace the broken tape with a new tape. In addition, what is needed is a tape measure with an improved adjustment mechanism for adjusting the tension of the spring within the cartridge. Furthermore, a housing with a comfortably positioned and easily operable lock switch is needed.

SUMMARY OF THE INVENTION

According to the invention, a tape measure assembly includes a housing having a tape receiving slot therein. A spool is rotatably mounted within the housing. A spring is connected to the spool for biasing the spool to rotate in one direction. A tape has an inner end connected to the spool and is coiled about the spool with an outer end passing through the tape receiving slot to the exterior of the housing. A hook or other retainer is connected to the outer end of the tape to retain the outer end of the tape outside of the housing. A lock mechanism is manually operable between a lock and release position for releasably maintaining the tape in a fixed position through the tape receiving slot. The lock mechanism includes a pressure regulator for regulating the locking pressure exerted on the tape by the lock mechanism.

According to another aspect of the invention, the lock mechanism has a manually operable button at the top of the tape measure housing and is movable in a vertical fashion between an upper release position and a downward lock position. Preferably, a spring biases the lock button to the release position. The lock button has an engaging shoulder for engaging the complementary shoulder in the housing for releasably retaining the lock button in the lock position against the bias of the spring.

Prefereably, the lock button has guide flanges for retaining the button in the housing when the lock means is in the release or lock position.

According to another aspect of the invention, a lock button for a tape measure includes a thumb engaging top portion and a downwardly depending front section that can form a front wall of the housing for the tape measure. The downwardly depending front section has a tape locking bottom end and rearwardly extending extensions that form the spring seat and the guide retaining flanges.

Preferably, the pressure regulating mechanism includes two resiliently flexible straps integrally formed with the front section connecting the tape locking buttom end with the rest of the front section.

In this fashion, a tape measure has a tape which can be easily locked in position or released from its locked position by pressure from an operator's thumb from the top of the housing. This provides for an easily operated tape measure which is comfortably held in the hand of the operator without any abnormal contortions to operate a poorly located lock button.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference now will be made to the accompanying drawings in which:

FIG. 1 is a top left perspective view of a tape according to the invention;

FIG. 2 is a top right perspective view of the tape measure shown in FIG. 1;

FIG. 3 is a lower and rear perspective view of the tape measure;

FIG. 4 is side elevational and partially segmented view of the tape measure with the first housing member removed;

FIG. 5 is a cross-sectional view taken along the lines V--V in FIG. 4.

FIG. 6 is a perspective view of the center axle and ratchet plate member;

FIG. 7 is a front elevational view of the lock button;

FIG. 8 is a side elevational view of the access door shown in FIG. 3;

FIG. 9 is a side elevational view similar to FIG. 4 showing the lock button in the lock position;

FIG. 10 is a side elevational and fragmentary view showing the spool and the connections of the spring with the axle and the inner end of the tape;

FIG. 11 is a fragmentary view of the connection of the tape to the spring taken along line XI--XI shown in FIG. 10;

FIG. 12 is a side elevational view of the interior of the second housing member; and

FIG. 13 is a side elevational segmented view similar to FIG. 4 showing a tape with a broken end retracted into the casing and with the access door in the open position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1, 2 and 3, a tape measure 10 has a housing 12 comprising a first member 14 and second member 16 which are secured together by screws 18a, b, c, and d. A sliding access door 17 is slidably mounted at the bottom of housing 12 and a lock button 19 is operably mounted at the front of housing 12. A metal tape 20 has its outer end 22 extending through slot 24 through the housing 12. The outer end 22 has a retaining hook 26 which can be used to hook onto objects to be measured and also retains the outer end 22 to the exterior of slot 24.

Referring now to FIGS. 4, 5, and 10, the tape 20 is coiled about a spool 28. The spool 28 has guide flanges 30 which guide and axially retain the tape 20. The spool 28 has a main body 29 and cover 31 snap fitted together by prongs 33 of body 29 extending through slots 35 in cover 31. The main body 29 has a cylindrical wall 32. A chamber 37 formed by cylindrical wall 32 contains a coil spring 36. The spring 36 has its outer tab end 38 passing through a slot 39 in cylindrical wall 32. As clearly shown in FIG. 11, the outer tab end 38 has a hole 35 and passes through aperture 41 at inner end 34 of tape 20.

The inner end 40 of spring 36 passes through a slot 42 in an axle 44 of an adjustment member 43. The spool 28 is rotatably mounted about the axle 44. The axle 44 in turn, has each end 45 and 47 rotatably mounted in two recessed journals 46 and 48 in housing members 14 and 16. The end 45 has a plastic end cap 51. Alternatively, the end 45 can be flat and not have end cap 51. The end 47 has a non-circular countersunk hole 53 that can receive an instrument, such as a screwdriver or Allen wrench.

The adjustment member 43 as shown in FIGS. 5 and 6, includes the axle 44 and an integrally formed radially extending plate 50 that has on its planar surface a plurality of ratchet teeth 52. The ratchet teeth as shown in FIG. 5 axially faces outwardly from the central plane 53 of the tape measure that is transverse to the axis of rotation of the axle 44 and spool 28.

The ratchet teeth 52 engage ratchet teeth 54, as shown in FIGS. 5 and 12, formed integrally with the second member 16. The ratchet teeth 54 face axially inwardly toward the central plane 53. The teeth 52 and 54 engage each other such that they allow only counter-clockwise rotation of the adjustment member 43 as shown in FIG. 4 or 12 (clockwise as viewed in FIGS. 2 and 3).

Furthermore, an elastomeric pad 56 made from rubber or preferably polyurethane is positioned within recess 46 to provide a resilient bias of the adjustment member 43 such that the ratchet plate 50 is biased against the ratchet teeth 54 in housing member 16. Alternatively, the housing itself may have some resilience which would eliminate the need for pad 56. Housing member 16 has journal 48 extend therethrough to form aperture 58 which provides access to hole 53 at end 47 from the exterior of housing 12. In addition to rotating the adjusting member 43 in the clockwise direction as viewed in FIG. 2 that loads the spring 36, the tool can be pressed when in the hole 53 to depress the member 43 against the bias of pad 56 or against the resilience of the housing to disengage ratchet teeth 52 from ratchet teeth 54 to allow the adjusting member 43 to move in a counter-clockwise direction as viewed in FIGS. 2 and 3 to unload spring 36.

Each housing member 14 and 16 has a horizontal flange 64 at its bottom edge with lower and upper facing shoulders 62 and 65 which provides a track 63 for the access door 17. The access door extends the full length of the bottom of housing 12. The door, as clearly shown in FIG. 8, has a front end 66 that forms a contoured bottom edge 67 of slot 24 and an abuttment for the retaining hook 26 of tape 20. The front end 66 has a flange 69 above edge 71 to form channel 73 which slidably receives track 67 of housing 12. The back upwardly curved end section 68 has an apertured section 75 with aperture 76 which receives screw 18d as shown in FIG. 1. The screw 18d can be removed and the door slid toward the rear to increase the size of slot 24 to form access port 78 as shown in FIG. 13. The edge 77 of front section 66 abuts post 79 that receives screw 18d to provide a stop for door 17.

Referring now to FIGS. 4, 7 and 9, the lock button 19 has a thumb operating section 80 which is at the top 82 of the housing within easy reach of the thumb when a hand holds the housing 12 in a normal fashion. A locking shoulder 81 extends rearwardly from section 80. The button 19 has front downwardly extending section 84 which provides a front wall of housing 12. The section 84 has two retaining flanges 86 which engage an interior flange 88 of housing 12 to retain the button 19 in position. In addition, section 84 has third extension 85 that has opposing retaining flanges 87 which engage interior flanges 89 of housing 12. The extension 85 also forms a spring seat 90 which holds coil spring 92 in place. Spring 92 has its lower end abutting a spring seat 94 on housing member 16. The button 17 has integral compression regulating straps 96 and a contoured tape engaging section 98.

In operation, the button 19 is normally biased by spring 92 upwardly to a release position. Shoulder 81 abuts the forwardly inclined edge 101 of housing 12. Upon depression of the top thumb section 80, the tape engaging section 98 moves downwardly to frictionally engage and clamp the tape 20 between it and the countoured surface 67 of access door 68. The downward vertical force exerted by the thumb causes shoulder 81 of thumb section 80 to engage shoulder 102 in the upper portion of housing 12. The compressed straps 96 and spring 92 produces an upward force which in turn produces friction between shoulders 81 and 102 maintains button 19 in the locked position. The straps 96 regulate the force exerted by tape engaging section 98 to prevent any excessive and permanently deforming force from being exerted onto the tape 20. A forward motion exerted on the thumb section 80 disengages the shoulders 81 and 102 and allows the spring 92 to release the button 19. Flanges 86 can abut web 91 of post 93 to provide an upper stop for button 19. The outer ends 97 of straps 96 are prevented from exiting channel 100 by shoulders 99, as viewed in FIG. 12.

Referring to FIG. 13, if the retaining hook 26 becomes disengaged from the tape 20 or the outer end 22 breaks in another fashion, the tape 20 recedes into the interior of the housing and allows the spool 28 to rotate (counterclockwise as shown in FIG. 13) to unload the spring 36. The tape cannot be easily retrieved until access to the interior is easily achieved. In this fashion, the lower right hand screw 18d can be removed and the access door 17 slid to the open position to increase the size of slot 24 to form access port 18 as described before. At this point, the tape end 22 can be easily grabbed and pulled back out from the housing interior. The access door is then reclosed and resecured with screw 18d while the tape end 22 is held. The tape is now pulled to totally unwind the tape 20 from spool 28 until the inner end 34 can be grabbed and disengaged from the tab end 38 of spring 36. The tab end 38 is maintained in position by insertion of a nail or similar object placed in hole 35. A new tape can have its inner end reattached to the tab end 38. At this point, a rewind tool can engage aperture 58 to crank the adjustment member 43 in a clockwise direction as shown in FIG. 3 until the spring is fully wound. A new tape 20 is then attached to tab end 38 and the nail is removed from hole 35. The new tape 20 is then free to rewind onto spool 28. The tape measure is then free to be used in its normal fashion.

In this fashion, reparable tape measure has an access port which allows easy access to the tape. More particularly, the slot 24 can be enlarged upon the sliding of the access door. Furthermore, the tape can be replaced without removal of the tape spool from its rotatably mounted position. In addition, an adjustment mechanism allows the spring to be correctly retensioned for the replacement tape. The lock button 19 is positioned to provide for comfortable and easy use in locking and releasing the tape.

Variations and modifications of the present invention are possible without departing from its scope and spirit as defined by the appended claims. 

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
 1. A tape measure characterized by:a housing having a tape receiving slot therein; a tape passing through said slot; tape receiving means mounted in said housing for receiving said tape; and a lock means normally biased towards an upper release position for releasably maintaining said tape in a fixed position through said slot, said lock means having an operable button at the top of said housing, said button vertically slidable between said upper release position and a lower lock position, said operable button integrally formed with a vertically slidable wall portion having means engaging said tape and forming a section of the exterior wall of said housing.
 2. A tape measure as defined in claim 1 further characterized by:spring means for biasing said lock means to a release position; engagement means for releasably retaining said lock means in a position to fix said tape against the bias of said spring means; guide means at the side of said wall portion for retaining said lock means with said housing when said lock means is in said release position or said lock position.
 3. A tape measure as defined in claim 2 further characterized by:said engagement means includes complementary shoulders on said lock means and on said housing.
 4. A tape measure as defined in claim 2 wherein said guide means includes;a first and second extension extending from a depending wall of said button; said extension having flanges that engage a forward shoulder of said housing.
 5. A tape measure as defined in claim 1 further characterized by:said lock means comprises the front wall of said housing.
 6. A tape measure characterized by:a housing having a tape receiving slot therein; a tape passing through said slot; tape receiving means mounted in said housing for receiving said tape; and lock means forming a portion of the vertical front wall of said housing for releasably maintaining said tape in a fixed position through said slot, said lock means having an operable button at the top thereof and extending through the top of said housing for slidably moving said lock means between an upper release position and a lower lock position, wherein said lock means includes: a wall portion forming a section of the exterior wall of said housing, said wall portion integral with said operable button; spring means for biasing said lock means to said release position; engagement means for releasably retaining said lock means in a position to fix said tape against the bias of said spring means; and guide means at the sides of said wall portion for slidably retaining said lock means with said housing when said lock means is in said release position and said lock position.
 7. The tape measure as defined in claim 6 wherein said engagement means includes complementary shoulders on said lock means and on said housing.
 8. The tape measure as defined in claim 6 wherein said guide means includes first and second extensions extending from the sides of said wall portion of said lock means, said extensions having flanges that engage a forward shoulder of said housing.
 9. A tape measure characterized by:a housing having a tape receiving slot therein; a tape passing through said slot; tape receiving means mounted in said housing for receiving said tape; lock means for releasably maintaining said tape in a fixed position through said slot and slidably movable between an upper release position and a lower lock position, said lock means forming a portion of the front wall of said housing; and means for biasing said lock means to said release position; said lock means including a manually operable thumb engaging portion, a wall portion extending downwardly from said thumb engaging portion and pressure regulator means for regulating the locking pressure on said tape by said lock means, wherein said pressure regulator means, said wall portion and said thumb engaging portion integrally form said lock means.
 10. The tape measure as defined in claim 9 and further comprising an extension extending rearwardly from the wall portion of said lock means, said rearward extension forming a spring seat.
 11. The tape measure as defined in claim 9 wherein said pressure regulating means includes two resiliently flexible straps integrally formed with said wall portion of said lock means connecting a tape engaging bottom end with said wall portion. 